The invention relates generally to a gate drive circuitry and, more particularly, to a gate drive circuitry for improving operating performances of Si and SiC semiconductor devices.
A wide range of applications requires electronic devices that operate at higher frequency, higher power, higher temperature, and in harsh environments. For example, electronic devices and sensors employed in deep space applications, high temperature applications, radiation polluted environment applications, jet engines, airborne microwave devices require such durable and high performance devices. Devices made using wide bandgap semiconductor materials such as silicon (Si), silicon carbide (SiC), gallium nitride (GaN), and diamond exhibit these properties. Generally, semiconductors having an energy difference or energy gap between the top of the valence band and the bottom of the conduction band typically greater than two electron volts (eV) are considered wide bandgap semiconductors. Such materials are generally chemically stable at high temperatures, have good thermal conductivity, a high breakdown field and a large electron saturation velocity.
For example, silicon carbide (SiC) based semiconductor devices, for example, are increasingly being employed in a wide range of power electronics applications due to their several superior characteristics when compared to silicon (Si) based semiconductor devices. In particular, SiC based semiconductor devices have superior thermal resistance, switching or operating speed, voltage blocking capability, and on-state voltage drop that cannot all be obtained with conventional Si based semiconductor devices. Additionally, due to the wide bandgap and/or blocking capability, SiC based semiconductor devices are suitable for high voltage applications.
Such semiconductor devices, including semiconductor devices having non-isolated input such as junction gated transistors (one example includes a junction field effect transistor (JFET), a static induction transistor (SIT), a bipolar junction transistor (BJT), and a metal semiconductor field effect transistor (MESFET)), require specialized gate drive or control circuitry for proper operation. Conventional gate drive circuitry typically does not perform well when required to drive non-isolated inputs devices. For example, applying conventional gate drive circuitry, such as those available for metal oxide semiconductor field effect transistors (MOSFETs) and insulated gate bipolar transistors (IGBTs), is not optimal for non-isolated input as the devices having non-isolated input, including wide bandgap semiconductor devices, require low and controlled gate voltages.
Normally-on SiC JFET has been used in some power electronics applications, however, the maximum current that the normally-on SiC JFET can handle is limited by the gate drive. Moreover, current gate drives, and gate drives developed for normally-on SiC JFETs fail to operate adequately or are limited in operating a normally-off SiC JFET. There have been some efforts to develop a gate drive that can work with wide bandgap semiconductor devices. However, the currently available and known gate drives do not operate a normally-off SiC JFET and/or do not operate the normally-on SiC JFET above their rated power for significant periods of time.
One embodiment of the present system provides an efficient and cost-effective gate drive circuitry customized for wide bandgap semiconductor devices and/or semiconductor devices having non-isolated inputs. It is also desirable to provide a gate drive that is able to operate a normally-on SiC JFET above their rated power for significant periods of time and/or operate a normally-off SiC JFET.